In the News

Preventing rabbits from causing serious plant damage

Cottontail rabbits cause extensive damage to ornamental plant nurseries in southern California by eating plants and damaging irrigation lines. With few methods to control the damage, UC Statewide Integrated Pest Management Advisor Cheryl Wilen and her field team used sophisticated technology to reduce the impact of rabbits.

Cottontail rabbit.
Photo by Tracy Ellis

Working closely with Pardee Tree Nursery in San Diego County and with funding from the California Department of Food and Agriculture Vertebrate Pest Research Advisory Committee, Wilen used Global Positioning System (GPS) technology to see how nursery practices and the incidence of rabbit damage are related, as well as to monitor the impact of experimental strategies to reduce their damage.

"California nursery growers report cottontail rabbits as the primary cause of breached irrigation lines and plant
damage," says Wilen. "One large commercial nursery in San Diego County reported more than $10,000 each year in direct plant loss and nearly $12,000 annually for repairing irrigation lines."

Itís illegal to bait cottontail rabbits in California, so growers must look at other options to control them. The team studied nursery characteristics such as irrigation type, container type, planting density, canopy width and height, and the incidence of rabbit damage. Exclusionary and restricted fencing with and without trapping was then tested in high-damage areas. The team also developed and tested various materials to protect irrigation tubing.

"We determined that trapping is not effective because even when a moderate number of rabbits were trapped, there were still more rabbits entering the area from surrounding areas and causing damage," says Wilen.

Wilen and her team experimented with electric and silt fencing. These types of fences are easy to install and remove. Results indicate that exclusionary fencing is an excellent temporary barrier, but it isnít practical in some situations because it hinders normal nursery operations such as moving stock or getting equipment into the area. It could, however, be used in problem plant beds.

Wilen also recommends modifying spaghetti irrigation tubing by covering it with larger polytubing or using a system where the tubing hangs down rather than lying on the ground. Also, since radio telemetry (putting a collar on the rabbits that gives a radio signal for their location) verified that rabbits had a number of preferred hiding places, nurseries can reduce refuges for the rabbits by getting rid of piles of waste materials such as wood and pallets, or fencing them off.

"From our research, we now know which nursery production practices are most vulnerable to damage, and it gives us another tool to measure the impact of IPM experimental control strategies."

Wilenís research partners are Tracy Ellis, Autumn Sartain, Ryan Miller, and Terrell Salmon of University of California Cooperative Extension, San Diego County.

Resources

High-resolution image (216KB) "Cottontail rabbit." Photo credit: Courtesy of UC Statewide IPM Program, Tracy Ellis. Photos are for use with this release only. All other uses see Legal Notices.

High-resolution image (332KB) "Plant damage." Photo credit: Courtesy of UC Statewide IPM Program, Autumn Sartain. Photos are for use with this release only. All other uses see Legal Notices.

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